1. Field of the Invention
The present invention relates to a content record terminal, a content record/reproduction system, a content recording method and the like for storing a video image content, a sound content or the like in a medium connected to a video image recording terminal.
2. Related Art of the Invention
In recent years, a video image distribution service which uses a communication network (communication line) has spread. In such a video image distribution system which includes a video image distribution server distributing a video image content or the like, a communication network consisting of a network outside a house, such as an Internet, and a network in the house, a video image receiving terminal apparatus connected to the network in the house (hereafter, expressed as a “video image receiving terminal”), and the like, a user can use a VOD (Video On Demand) service, IP (Internet Protocol) broadcasting, a video image download service and the like which are provided from a video image server of a communication enterprise or a video image distribution enterprise, by operating the video image receiving terminal used for viewing the video image.
FIG. 8 shows a diagram for describing processing details of the video image content, in a conventional video image download service.
In a conventional video image download service, as shown in FIG. 8, a video image receiving terminal 200 downloads a video image content from a video image distribution server 210 and stores the content in the built-in HDD 201.
The video image receiving terminal 200 is permitted to reproduce the video image content by a viewing license which is acquired when the video image content is purchased. Then the video image receiving terminal 200 can decrypt and output the video image content stored in the HDD 201. The video image receiving terminal 200 outputs the video image content to a display 202 connected or the like, and the video image content can be viewed. When writing the video image content into another medium is permitted, the video image receiving terminal 200, after decrypting the video image content stored in the HDD 201 and encrypting the decrypted content to export, can also write the video image content into a removable medium 203.
When the video image download service is used, the video image content has to be managed.
For example, the video image distribution server 210 side which distributes the video image content has to recognize whether the video image content has been downloaded correctly or not for permitting the video image receiving terminal 200 to reproduce the video image content. For a video image content in a rental service in which a viewing term is limited, the video image receiving terminal 200 side performs deleting of the video image content promptly when a viewing expiration time limit expires.
As explained above, rights of a service enterprise and a user can be protected by managing the video image content appropriately.
A method, in which the video image distribution server checks a completion of download of the video image content by acquiring another different license from a viewing license from the video image distribution server before the download service is performed for managing the video image content appropriately, is disclosed (see, for example, Patent Document 1 (International Publication No. 2008-146913)).
In the check method of the completion of download of the video image content in the Patent Document 1, first, the different license from the viewing license is acquired before the download of the video image content is started. Since a time short enough is set up as an expiration time limit of the license, the license cannot be used for reproducing the video image content. When the video image receiving terminal completes the download of the video image content, the video image receiving terminal requests to acquire the viewing license to a DRM (Digital Right Management) server of the service enterprise by using the license. The DRM server can recognize the completion of the download of the video image content in the video image receiving terminal by the request to acquire the viewing license.
As described above, a check of the completion of the download of the video image content is realized at the server side.
However, in the above conventional download service, there is a problem that a part that is downloaded of the video image content remains in a recording medium to record in the video image receiving terminal when the download of the video image content is interrupted.
The download of the video image content has a high possibility of being interrupted. External factors such as power discontinuity or internal factors such as starting of another application can be considered as causes of the interruption.
When the download is suddenly interrupted due to such causes, an incomplete video image content which has not been downloaded completely remains in an HDD or a removable medium which is a recording medium in the video image terminal side. Such an incomplete video image content may remain in the recording medium as what is called a garbage file.
Such a garbage file presses the capacity of the recording medium. Furthermore, an opportunity of analyzing the video image content is given to a malicious user or a malicious terminal. The expiration time limit of the license, which is used in the check method of the completion of download of the video image content in the Patent Document 1, is set as a time short enough because the license is used to manage the completion of the download. Therefore, when the expiration time limit of the license expires, some video image receiving terminals delete only the licenses, and so that data of the video image content may remain as it is.
When especially the video image content is recorded on the removable medium, carrying to other terminals is easy and it becomes easy for the malicious user to analyze the video image content.
In view of the above-described conventional problems, it is an object of the present invention to provide a content record terminal, a content record/reproduction system, a content recording method and the like, which can delete a garbage file having the incomplete video image content appropriately even when a recording process of a video image content to a recording medium is interrupted.